Jeep Cherokee Engines - RENIX Camshaft Position Sensor / Sync Pulse (Stator) Replacement

Follow the procedure for testing the RENIX CAMshaft Position Sensor / Sync Pulse (Stator) Test first!

This article is intended to help you replace a faulty ignition system 'stator / camshaft position sensor after it fails. The camshaft position sensor (aka 'stator' or sync pulse generator) lets the ECU know when to pulse the fuel injectors and co-ordinates with the Crankshaft Position Sensor for engine timing.

WARNING!: The term CPS is most often used to describe the CRANKshaft position sensor! Be SURE to get the correct sensor! Both the crank and cam position sensors work together feeding the ECU (computer) information on the engine timing to fire the injectors and maintain engine timing. In the case of the Jeep 4.0L engine: the CAMshaft position sensor is also called the 'sync pulse generator' (or stator) and can be found in the "distributor" while the CRANKshaft position sensor is located on the transmission bellhousing. (* See bottom of RENIX Stator Test Procedure page)

Don't be surprised if your counter drone tries to hand you the wrong part as there are several common names in use for the Camshaft Position Sensor:

camshaft position sensor
stator
sync-pulse generator
"...Auto Zone had the (sync signal generator) but they call it a pick-up coil..." (from a post at JU)

Jeep 4.0L Distributor Stator Parts "exploded diagram".

Overhead diagram view of Jeep 4.0L "distributor" internal parts and stator / sync pulse generator / CAMSHAFT position sensor.

This article begins after you have followed the RENIX Stator Test Procedure.

Yes, Toto... you aren't in Kansas anymore. You have to pull the freaking distributor to change the stator!

RENIX STATOR REMOVAL

Remove distributor cap leaving wires in place and connected to plugs. This will save ya some headaches later. Just set it outta the way.
Pull the distributor by following the Distributor Removal & Installation Procedure as found in your service manual. (I'll get an article up on that at some point but basically ya set the engine to TDC (top dead center), bump the rotor so that it is parallel to the engine block and pointing forward, mark the rotor's direction on the distributor, remove the distributor bolt, rotate the rotor a bit as you gently pull the distributor out. DO NOT ENGAGE ENGINE STARTER NOW OR YOU'LL HAVE TO FIND TDC THE HARD WAY!!!
Remove rotor.
Place distributor shaft in a vice being careful not to overtighten or damage the surface. (See Fig. 33 below).
Knock out the drive gear's retaining pin with a small, FLAT punch. The retaining pins are commonly called roll pins and can be found in most hardware stores. (See Fig. 33 below).
Once ya have the pin out - grab it and put it somewhere safe... NO! You won't be reusing it but you will be using it to buy ya another one to replace it. I do not recommend ya reuse these unless the possibility of having one drop out inside your engine and your camshaft eating the distributor drive gear sounds like a fun thing.
Put the drive gear, washer & gasket in a safe place so they do not wander off and then remove the distributor shaft & pulse ring from the shaft housing. Everything is free now that you have the gear off.
Take an awl, or finishing nail and mark the stator location before removing the retaining screw, then remove the screw. (See Fig. 34 below).
You'll have to press the grommet around the stator's wiring harness INTO the distributor then you can fish the harness on through and remove the assembly. Your new harness SHOULD have a new grommet. If it does not, be sure to pick up a new grommet as distributors do not like moisture... and you do not like walking home at 3 AM on a rainy night.

After removing the distributor... you need to remove the drive gear.

RENIX Stator Replacement

How ya do this part depends on how clumsy you are... For some it will be easier to fish the stator pigtail through the opening in the distributor housing first - for others it's easier to fish the pigtail through afterwards.
Either way - using the marks you scratched on the inside of the distributor, install your new stator being sure to reinstall the retaining screw and hold down shown.
If you haven't already done so, fish the stator harness through the harness hole & press the grommet securely into place. (* - Hint: A very few drops of dish soap (or spit) on the grommet will help it slip into place when the time comes. You most likely will NOT need to do this.)
Reinstall the distributor shaft into the distributor housing. Make sure any seals are intact and undamaged.
Replace the drive gear gasket, washer and then the drive gear onto the shaft. Be sure ya put the gear on the same way ya took it off or your engine will do bad things. Very bad things. And then you'll cry. (It's hard to mess this up but some people work extra hard and have big hammers. Just watch it and you'll be fine!)
Install your NEW drive gear retaining pin (roll pin). (Again - don't reuse the old one. Yes... you likely can get away with it... but for .30 cents or so do you really want to chance blowing an engine?)
Put the rotor back on and reinstall the distributor using the procedure outlined in the Distributor Removal & Installation Procedure as found in your service manual.

Here is another exploded diagram of the complete 4.0L distributor that shows ALL parts to help ya in the disassembly / reassembly process. Just don't lose any parts and use a new roll pin... you'll be fine!

Here's a complete diagram of all the parts in a Jeep 4.0L RENIX distributor. The dealer will have the oddball parts not available at your local auto parts store & the roll pin is commonly available at any good hardware store (like True Value).
I'll get some pics up next chance I get to pull the distributor for no apparent reason.

If you have pics of your own repairs or can suggest other methods - please contribute your ideas (and pictures) to this article!

Revised on: June 6th, 2007